etective Jane Tennison is arguably Helen Mirren’s most famous role, and given the amount of time she invested in the part – roughly 25 hours over the course of 15 years – that shouldn’t come as a big surprise. Then again, what’s 25 hours in the grand scheme of TV? That’s only a few hours longer than one season of a typical American drama. Doesn’t sound like all that much, does it? Then it must be the quality of this dense work that makes it so worthy. In order to understand what makes “Prime Suspect” must-see TV on DVD, it helps to know the structure of the show.

In lieu of traditional episodic seasons, the show offers up a single storyline for each of its seven seasons, and each of those stories is comprised of two 100-minute blocks, so the stories are effectively comprised of two feature-length installments. (Only “Prime Suspect 4” bucks the trend by offering three standalone 100-minute tales instead.) Through this structure, “Prime Suspect” is able to explore Tennison’s cases in an unusually thorough manner, and I dare suggest that this material will be best appreciated by the hardcore procedural enthusiast. If this is your kind of fare, then you owe it to yourself to see this set.

These stories twist and turn with all sorts of red herrings, roadblocks, and detours for Tennison and the various teams she works with over the course of her career. It’s easy when watching these stories to feel as if you’re caught up in an actual investigation, or perhaps it’s more like being a fly on the wall viewing the sordid proceedings. This lengthy structure also allows the stories to focus on Tennison’s tumultuous personal life, which builds and breaks down from one story to the next, taking place in a real time of sorts. The first story was made in 1991 and the finale in 2006, so as the viewer, we’re essentially getting these intense, sporadic explorations of Tennison’s life and career over a 15-year period. Sure, there’s a certain amount of dot-connecting viewers have to do as the years pass, but there’s just enough information presented in each new story that you can do that without much difficulty, and as a result the experience is nothing less than rich and rewarding.

The title of the show is best applied to the first story, in which Tennison must fight her way through sexist colleagues and endless red tape to lead an investigation into the brutal deaths of several women. (In the U.K., this was practically unheard of for a woman at the time.) The prime suspect in question is one George Marlow (John Bowe), but why does the guy seem so innocent? It’s a fascinating cat and mouse game, and one that drags you into Jane’s world. After watching it, you’ll be hooked. (Keep an eye out for a very young Ralph Fiennes, who’s only in one or two scenes.)

“Prime Suspect 2” delves into racism, and explores the friction between an Afro-Caribbean neighborhood and the police force, when a young woman’s body is unearthed in somebody’s backyard. “Prime Suspect 3”, which deals with rentboys, drag queens and a pornography ring, is noteworthy for the guest cast alone: David Thewlis, Peter Capaldi, Jonny Lee Miller, Mark Strong, James Frain and Ciarán Hinds.

And so it goes, until the seventh series, subtitled “The Final Act,” which sees Tennison investigating the death of a teenage girl, with shocking results. It’s a fitting swan song for the character, as you genuinely sense that she’s no longer working at the top of her game, and that alcoholism has taken its toll, with the bottle being her only reliable companion. No, “Prime Suspect” isn’t a pleasant watch, but it’s a damn good one.

Given that over the course of seven seasons there are only nine stories here, it perhaps goes without saying that “Prime Suspect” doesn’t afford itself the opportunity for repetition. Each storyline feels fresh and new. Watching the entirety of it over a couple weeks can be a wearing, depressing experience, as this show is relentlessly dark, and it isn’t something I’d recommend. On the other hand, this collection is highly recommended, but take your time viewing it, and savor these stories over a period of months. Don’t be in a hurry to devour the whole thing as soon as possible simply because you can. Only reviewers like me need subject themselves to such an arduous, but ultimately exciting, TV timetable.

Special Features: The first five series have no extras whatsoever. Series Six has a 23-minute behind-the-scenes featurette, and Series Seven has a 50-minute documentary on the concept as a whole, in addition to a photo gallery and cast filmographies. Not much, but maybe just enough.